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  • 1
    Electronic Resource
    Electronic Resource
    Forms of atypical depression and their response to antidepressant drugs
    Amsterdam : Elsevier
    Psychiatry Research 17 (1986), S. 87-95 
    Details
    ISSN: 0165-1781
    Keywords: Atypical depression ; drug response ; gender ; panic
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0165-1781(86)90063-6
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental determination of the behaviour of heat-resisting alloys in complex atmospheresDedicated to Professor Dr. Alfred Rahmel on the occasion of his 60th birthday (1987)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 38 (1987), S. 606-613 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Experimentelle Bestimmung des Verhaltens von hitzebeständigen Legierungen in Atmosphären komplexer ZusammensetzungKonstrukteure technischer Anlagen stehen oft vor dem Problem der Hochtemperaturkorrosion in Atmosphären komplexer Zusammensetzung. Die Auswahl und Entwicklung von wirtschaftlich und technisch geeigneten neuen Werkstoffen für solche Anwendungen erfordert Prüfstände, die die wahren Betriebsbedingungen so nahe wie möglich simulieren.Zu diesem Zweck wurde eine neue Laboratoriumseinrichtung gebaut, mit welcher genau definierte Gemische aus bis zu vier Gasen (gegebenenfalls noch mit Wasserdampf) hergestellt werden können. Dadurch ist es möglich, die Aktivitäten von Sauerstoff, Wasserstoff, Kohlenstoff und Schwefel bei der Betriebstemperatur festzusetzen. Die Gaszusammensetzung wird an verschiedenen Stellen des Prüfstands chromatographisch überwacht.Die ersten Versuche wurden mit drei FeCrNi-Legierungen durchgeführt, die Gasgemischen (CO/CH4/H2/H2S) ausgesetzt wurden, deren Zusammensetzung den Verhältnissen in Kohlevergasungseinrichtungen entspricht. Die bisherigen Beobachtungen zeigen, daß wegen der verwendeten niedrigen Sauerstoffpartialdrucke die mehrschichtigen Zunder hauptsächlich aus Sulfiden bestehen. Diese Ergebnisse werden mit den Werten verglichen, die sich aus berechneten thermodynamischen Phasenstabilitätsdiagrammen ableiten lassen.
    Notes: Designers of industrial plants are often confronted with problems of high temperature corrosion in complex atmospheres. The selection and development of economically and technically viable new materials for such applications requires the use of experimental rigs capable of simulating as closely as possible the real operating conditions.With this aim, a new laboratory installation has been built, which enables precisely defined mixtures of up to four gases to be obtained (plus water vapour, if required). It is thus possible to fix the activities of O, H, C and S at the working temperature. The composition is monitored at various points in the rig, using a chromatograph.The first tests were carried out on three Fe-Cr-Ni alloys exposed to complex gas mixtures (CO/CH4/H2/H2S) similar to those encountered in coal-gasification plant. The observations show that, due to the low oxygen partial pressures, the multi-layered scales are composed mainly of sulphides. These results are compared with predictions based on calculated thermodynamic phase stability diagrams.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19870381009
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  • 3
    Electronic Resource
    Electronic Resource
    The pyrolytic LCVD of high-purity gold tracks from alkyl (trialkylphosphine) gold(I) complexes (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Advanced Materials for Optics and Electronics 2 (1993), S. 3-17 
    Details
    ISSN: 1057-9257
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: The pyrolytic LCVD of high-purity gold tracks from the organogold(I) complex MeAuPMe3 is reported. The tracks were deposited onto (100) n-type single-crystal silicon with a thermally grown oxide layer (3000 Å), single-crystal GaAs with an intact native oxide layer and polycrystalline diamond films upon (100) silicon using the output from an argon ion laser (Coherent Innova 100-10) at 514.5 nm. Deposits were grown at a range of scan speeds from 0 to 200 μm s-1 and characterised by SEM, SIMS, LIMA and scanning profilometry. Electrical resistivities as low as 7.04 μΩ cm, within a factor of three of that of bulk gold, were achieved at scan speeds below 156.3 μm s-1. These are consistent with deposit purities of better than 99% (LIMA) without the need for a post-deposition annealing step.The relationship between power density, beam residence time and deposition rate was measured. The morphology of the deposit from the onset of detectable nucleation through to the formation of continuous tracks was analysed by SEM micrographs of deposits grown at successively increasing power densities. The nucleation process was found to be substrate-dependent. Changes in deposit morphology with power density and scan speed were observed. These include periodicity in track width and at high power densities the development of ‘volcano’-shaped profiles.The formation of a phosphorus-based interfacial layer, exclusive to laser deposition upon GaAs, is evidence for a reaction between the PMe3 and GaAs.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/amo.860020103
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  • 4
    Electronic Resource
    Electronic Resource
    Histological response to cylinders of a low modulus titanium alloy (Ti-13Nb-13Zr) and a wear resistant zirconium alloy (Zr-2.5Nb) implanted in the rabbit tibia (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Biomaterials 4 (1993), S. 331-339 
    Details
    ISSN: 1045-4861
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: To assess new and existing materials for total joint arthroplasty, the authors performed a comprehensive histomorphologic and morphometric analysis of bone to cylinders implanted transversely in the proximal tibia of mature New Zealand white rabbits. Four sterile, cylindrical implants measuring 6.1 × 3.8mm were manually inserted through drill holes in both tibiae with a „line-to-line fit.“ The materials tested included: ASTM F-75 cast cobalt-chrome-molybdenum alloy, commercially pure titanium wrought zirconium-2.5 niobium alloy, zirconium oxide coated zirconium-2.5 niobium alloy, wrought titanium-13 niobium-13 zirconium alloy, and nitrogen diffusion hardened titanium-6 aluminum-4 vanadium alloy. Control animals with or without drill holes were included. The animals were killed by barbiturate overdose 6 months postoperatively. The upper tibiae were harvested and processed for undecalcified histologic sections that were stained with toluidine blue. The sections were examined by an investigator blind to the identity of the implanted materials. A full necropsy was also performed.A collar of lamellar bone, of variable length and thickness, continuous with the original cortex formed a buttress around the implants. There was no evidence of foreign body or inflammatory reaction. The marrow was slightly fatty, but cells of allthree hematopoietic lines were identifiable. The materials investigated had the following ranking in decreasing order of bone contact: Ti-13Nb-13Zr 〉 nitrogen hardened Ti-6Al-4V 〉 C.P. titanium 〉 Zr 2.5Nb 〉ZrO2 coated Zr-2.5Nb 〉 cast Co—Cr alloy. The difference between the groups was statistically significant (p = 0.05). For the variable „average bone layer thickness“ the ranking in decreasing order was: nitrogen hardened Ti-6Al-4V alloy = C.P. titanium 〉 Ti-13Nb-13Zr 〉 ZrO2/Zr-2.5Nb 〉 Zr-2.5Nb 〉 cast Co—Cr alloy (p = 0.19). For the variable „average bone layer thickness in bone contact regions,“ the ranking of the values, in decreasing order were: nitrogen hardened Ti-6Al-4V 〉 C.P. titanium 〉 ZrO2 coated Zr-2.5Nb 〉 Ti-13Nb-13Zr 〉Zr-2.5 Nb 〉 cast Co—Cr alloy (p = 0.02). The final necropsy reports of the animals identified no adverse findings that were concentrated to any particular implant group. The new, lower modulus materials Ti-13Nb-13Zr and Zr-2.5 Nb, and nitrogen hardened Ti-6Al-4V appear to have a similar or superior bone response to Co—Cr alloy when implanted in the rabbit tibia model. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jab.770040407
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  • 5
    Electronic Resource
    Electronic Resource
    Heat transfer analysis of frictional heat dissipation during articulation of femoral implants (1988)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 22 (1988), S. 281-309 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Previous studies have shown the tendency for frictional heating to occur during articulation of total hip systems in vitro under simulated hip loading conditions. The magnitude of this heating is sufficient to accelerate wear, creep, and oxidation degradation of the UHMWPE bearing surface. It was shown that ceramic articulating systems generate less frictional heating than polished cobalt alloy against UHMWPE. This fricitonal heating is expected to occur primarily for younger, heavier, and more active patients. Thus, long-term performance of the articulating hip system in these patients may not be that predicted from current, body-temperature wear, creep, and degradation studies. Although the tendency to generate frictional heat has been observed only during in vitro simulated hip loading, a heat transfer analysis of this phenomenon is presented to evaluate the ability of the hip joint to dissipate such heating in vivo. Additional experiments were performed using controlled resistance heaters inside a cobalt femoral head to verify the calculated levels of frictional heat and to assess the heat dissipation under simulated in vivo conditions. The effect of blood perfusion on the effective thermal conductivity of the joint capsule is also discussed. The present study describes and analyzes the various heat dissipation mechanisms present both in vitro and in vivo during articulation of metal and ceramic hip systems. From these tests and analyses, it is concluded that frictional heating in the reconstructed hip cannot be effectively removed, and that degredative elevated temperature processes can be expected to occur in vivo to both the UHMWPE and adjacent tissue under extended periods of excessive patient activity. This is particularly true for metal cobalt alloy femoral heads articulating on UHMWPE versus ceramic heads which generate significantly lower levels of heat.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820221408
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  • 6
    Electronic Resource
    Electronic Resource
    Combined chemical and mechanical effects on free radicals in UHMWPE joints during implantation (1991)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 25 (1991), S. 1005-1017 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: An electron spin resonance (ESR) technique is employed to determine the free radical distribution in the articulating surfaces of retrieved acetabular cups and knee-joint plateaus (retrieved after more than 6 years of implantation). Similar measurements made on samples prepared from cyclically stressed and unstressed cups, and on samples following oxidations in nitric acid and intralipid solutions provided sufficient data to gain more knowledge about the combined chemical and mechanical effects on PE free radicals during implantation. In UHMWPE free radicals are primarily initiated by gamma-ray sterilization; however, during implantation, peroxy (scission type) free radicals are formed and reach a maximum concentration level (equilibrium state) due to oxidation by chemical (hemoglobin and/or synovial fluids) environment of the joints. Subsequently, due to frictional heating and stress in the loading zones, free radical reaction is accelerated and their number is reduced only in those areas. This is consistent with the observations of a temperature rise in acetabular cups during in vitro frictional wear stress tests and in vivo telemetry observations, as reported by others. Compared with the previously reported SEM micrographs the low-free-radical regions are correlated with high-wear areas and the high-free-radical regions with the low-wear areas.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820250807
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  • 7
    Electronic Resource
    Electronic Resource
    Initial hemocompatibility studies of titanium and zirconium alloys: Prekallikrein activation, fibrinogen adsorption, and their correlation with surface electrochemical properties (1996)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 32 (1996), S. 77-85 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Two novel metal alloys, Ti-13Nb-13Zr and Zr-2.5Nb, have been engineered for applications in orthopedic implants because of their favorable mechanical properties, corrosion resistance, and compatibility with bone and tissue. These alloys also have the ability to form a hard, abrasion-resistant, ceramic surface layer upon oxidative heat treatment (diffusion hardening, DH). Previous studies have indicated that these and other ceramics cause limited hemolysis and exhibit remarkable structural integrity after extended exposure to physiological environments. Such observations suggest that DH Ti-13Nb-13Zr and ZrO2/Zr-2.5Nb could be used successfully as components in blood-contacting devices. Materials intended for such applications must possess properties that do not elicit adverse physiological responses, such as the initiation of the coagulation cascade or thrombus formation. In the present study measurements of prekallikrein activation, fibrinogen adsorption from diluted human plasma, and the strength of fibrinogen attachment as judged by residence-time experiments were performed to evaluate the potential hemocompatibility of these materials. The results of the prekallikrein activation and fibrinogen-retention studies correlated well with two electrochemical properties of the alloys, the open circuit potential and reciprocal polarization resistance. The results indicate that both the original and treated Ti and Zr alloys activate prekallikrein and adsorb as well as retain fibrinogen in amounts similar to other materials used as components of blood-contacting devices. On the basis of these studies, these alloys appear to be promising candidates for cardiovascular applications and merit further investigation. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    The effect of HIPing on the fatigue and tensile strength of a cast, porous-coated Co—Cr—Mo alloy (1986)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 20 (1986), S. 1229-1248 
    Details
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: The process required to sinter porous Co=Cr=Mo alloys results in the formation of substrate porosity through carbide dissolution. Since hot isostatic pressing (HIPing) has been shown to eliminate casting porosity in the Co=Cr=Mo alloy, it is possible that it may be equally effective on pores that are generated from the sintering operation. The effect that HIPing a porous-coated Co=Cr=Mo material has on the fatigue and tensile properties was investigated. Fatigue testing was performed on sintered materials as well as sintered and HIPed materials, both with and without a porous coating. Further, the effect of varying coating thickness on the resulting fatigue strength of sintered and HIPed materials was studied. Light microscopy was performed in order to define the microstructural changes brought about by the various thermal cycles. Scanning electron microscopy was utilized to define the crack initiation process. The fatigue strength of uncoated “as sintered” materials was found to be reduced by 34% relative to the “as cast” condition. The same material that was HIPed revealed a fatigue strength slightly lower than the “as cast” condition. It was found that porous coatings created preferential sites for fatigue crack initiation. However, the presence of the coating did not further reduce the fatigue strength of “as sintered” materials because of the already low strength created by the sintering operation. Materials that were sintered exhibited a lowering in both tensile strength and elongation to failure relative to the “as cast” condition. The HIPing of sintered materials improved both fatigue and tensile properties relative to the “as sintered” condition.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jbm.820200812
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  • 9
    Electronic Resource
    Electronic Resource
    Particle structure of suspension poly(vinyl chloride) and its origin in the polymerization process (1980)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 18 (1980), S. 51-69 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The initial stage of the suspension polymerization of poly(vinyl chloride) (PVC) is characterized by the formation of colloidally stable micron-sized grains of PVC inside the polymerizing ca. 150 μm vinyl chloride droplets. The fate of these micron-sized PVC grains depends upon the agitation conditions. If no agitation is employed, they serve as growth centers for further polymerization to give a final particle possessing a uniform internal bead morphology. In agitated systems, these grains coagulate early in the conversion to give a more irregular structure in the interior of the PVC particle. The formation of these stable growth centers appears to be unique to PVC. The polymerization of acrylonitrile, also insoluble in its monomer, is characterized by rapid agglomeration of the precipitated polymer throughout the polymerization. In PVC, the colloidal stability of the polymerizing grains is demonstrated to be electrical in nature. A pericellular membrane or skin formed by polymerization in both the water and vinyl phase completely surrounds the polymerizing droplet after about (1-2)% conversion. This skin is responsible for the charge retention of the PVC grains inside the polymerizing monomer droplets.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1980.180180105
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